Don’t worry, those aren’t extra-terrestrial crop circles. And actually, this is going on one block south of 5th and L. The round installations popping up around the CityVista residential and retail complex aren’t anything nefarious, unless you object to a bit of greening on the sidewalk. The District Department of Transportation is installing large planters around Mt. Vernon Triangle as part of its redevelopment of K Street NW, spokesman John Lisle says. Since last March, crews have been chopping up sections of the busy, but not very beautiful, stretch of K Street between 7th Street and New Jersey Avenue. And some of the planters are already in place, though obviously not in full bloom right now; Phase 4 of the project is responsible for the trees and bushes potted outside Busboys and Poets, while Phase 6 will do the same on the opposite side of the street. The entire venture is scheduled to be complete in June, by which point DDOT expects K Street to be transformed from a smashed-up strip of potholes into something more pleasant for drivers, cyclists, and pedestrians. And if the aliens are coming, at least they’ll know where to land.